U.S. Pat. No. 5,746,919 teaches a temperature-phased anaerobic waste treatment process wherein waste is passed through a thermophilic biofilter first and then a mesophilic biofilter, wherein the biofilter media is made of random packed material or modular vertical or cross-flow media. Because of the use of the biofilter media, this process appears to be poorly suited for use with waste containing solid matter. Furthermore, a considerable input of energy is needed to heat cold waste to a thermophilic temperature range.